* Re: FAILED: patch "[PATCH] auxdisplay: charlcd: properly restore atomic counter on error" failed to apply to 4.9-stable tree
2017-10-10 15:03 FAILED: patch "[PATCH] auxdisplay: charlcd: properly restore atomic counter on error" failed to apply to 4.9-stable tree gregkh
@ 2017-10-10 20:22 ` Willy Tarreau
2017-11-12 13:09 ` Willy Tarreau
1 sibling, 0 replies; 4+ messages in thread
From: Willy Tarreau @ 2017-10-10 20:22 UTC (permalink / raw)
To: gregkh; +Cc: geert, marius.gorski, miguel.ojeda.sandonis, stable
Hi Greg,
On Tue, Oct 10, 2017 at 05:03:43PM +0200, gregkh@linuxfoundation.org wrote:
>
> The patch below does not apply to the 4.9-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.
I'll provide you with the backports for 4.9 and 4.4 probably next week
(3.18 not needed).
Cheers,
Willy
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: FAILED: patch "[PATCH] auxdisplay: charlcd: properly restore atomic counter on error" failed to apply to 4.9-stable tree
2017-10-10 15:03 FAILED: patch "[PATCH] auxdisplay: charlcd: properly restore atomic counter on error" failed to apply to 4.9-stable tree gregkh
2017-10-10 20:22 ` Willy Tarreau
@ 2017-11-12 13:09 ` Willy Tarreau
2017-11-16 17:41 ` Greg KH
1 sibling, 1 reply; 4+ messages in thread
From: Willy Tarreau @ 2017-11-12 13:09 UTC (permalink / raw)
To: gregkh; +Cc: geert, marius.gorski, miguel.ojeda.sandonis, stable
[-- Attachment #1: Type: text/plain, Size: 214 bytes --]
Hi Greg,
as promised a month ago, here finally come the tested backports of this
fix for 4.9 and 4.4 respectively. This backport is not needed for 3.18
as the regression was introduced in 3.19-rc1.
Cheers,
Willy
[-- Attachment #2: panel-4.4.patch --]
[-- Type: text/plain, Size: 2394 bytes --]
>From 29e391ca59d60b7902b09ed11edbc5c95c372f09 Mon Sep 17 00:00:00 2001
From: Willy Tarreau <w@1wt.eu>
Date: Thu, 7 Sep 2017 11:56:40 +0200
Subject: misc: panel: properly restore atomic counter on error path
Commit f4757af ("staging: panel: Fix single-open policy race condition")
introduced in 3.19-rc1 attempted to fix a race condition on the open, but
failed to properly do it and used to exit without restoring the semaphore.
This results in -EBUSY being returned after the first open error until
the module is reloaded or the system restarted (ie: consecutive to a
dual open resulting in -EBUSY or to a permission error).
Fixes: f4757af85 # 3.19-rc1
Cc: stable@vger.kernel.org [3.19+]
Cc: Mariusz Gorski <marius.gorski@gmail.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
[wt: driver is in staging/panel in 4.4]
---
drivers/staging/panel/panel.c | 23 +++++++++++++++++++----
1 file changed, 19 insertions(+), 4 deletions(-)
diff --git a/drivers/staging/panel/panel.c b/drivers/staging/panel/panel.c
index 70b8f4f..e658e11 100644
--- a/drivers/staging/panel/panel.c
+++ b/drivers/staging/panel/panel.c
@@ -1431,17 +1431,25 @@ static ssize_t lcd_write(struct file *file,
static int lcd_open(struct inode *inode, struct file *file)
{
+ int ret;
+
+ ret = -EBUSY;
if (!atomic_dec_and_test(&lcd_available))
- return -EBUSY; /* open only once at a time */
+ goto fail; /* open only once at a time */
+ ret = -EPERM;
if (file->f_mode & FMODE_READ) /* device is write-only */
- return -EPERM;
+ goto fail;
if (lcd.must_clear) {
lcd_clear_display();
lcd.must_clear = false;
}
return nonseekable_open(inode, file);
+
+ fail:
+ atomic_inc(&lcd_available);
+ return ret;
}
static int lcd_release(struct inode *inode, struct file *file)
@@ -1704,14 +1712,21 @@ static ssize_t keypad_read(struct file *file,
static int keypad_open(struct inode *inode, struct file *file)
{
+ int ret;
+
+ ret = -EBUSY;
if (!atomic_dec_and_test(&keypad_available))
- return -EBUSY; /* open only once at a time */
+ goto fail; /* open only once at a time */
+ ret = -EPERM;
if (file->f_mode & FMODE_WRITE) /* device is read-only */
- return -EPERM;
+ goto fail;
keypad_buflen = 0; /* flush the buffer on opening */
return 0;
+ fail:
+ atomic_inc(&keypad_available);
+ return ret;
}
static int keypad_release(struct inode *inode, struct file *file)
--
1.7.12.1
[-- Attachment #3: panel-4.9.patch --]
[-- Type: text/plain, Size: 2346 bytes --]
>From 7ddfddb3fc0afb2aa36e89b554f06c901c5fa36f Mon Sep 17 00:00:00 2001
From: Willy Tarreau <w@1wt.eu>
Date: Thu, 7 Sep 2017 11:56:40 +0200
Subject: misc: panel: properly restore atomic counter on error path
Commit f4757af ("staging: panel: Fix single-open policy race condition")
introduced in 3.19-rc1 attempted to fix a race condition on the open, but
failed to properly do it and used to exit without restoring the semaphore.
This results in -EBUSY being returned after the first open error until
the module is reloaded or the system restarted (ie: consecutive to a
dual open resulting in -EBUSY or to a permission error).
Fixes: f4757af85 # 3.19-rc1
Cc: stable@vger.kernel.org [3.19+]
Cc: Mariusz Gorski <marius.gorski@gmail.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
[wt: driver is in misc/panel in 4.9]
---
drivers/misc/panel.c | 23 +++++++++++++++++++----
1 file changed, 19 insertions(+), 4 deletions(-)
diff --git a/drivers/misc/panel.c b/drivers/misc/panel.c
index 6030ac5..a9fa4c0 100644
--- a/drivers/misc/panel.c
+++ b/drivers/misc/panel.c
@@ -1423,17 +1423,25 @@ static ssize_t lcd_write(struct file *file,
static int lcd_open(struct inode *inode, struct file *file)
{
+ int ret;
+
+ ret = -EBUSY;
if (!atomic_dec_and_test(&lcd_available))
- return -EBUSY; /* open only once at a time */
+ goto fail; /* open only once at a time */
+ ret = -EPERM;
if (file->f_mode & FMODE_READ) /* device is write-only */
- return -EPERM;
+ goto fail;
if (lcd.must_clear) {
lcd_clear_display();
lcd.must_clear = false;
}
return nonseekable_open(inode, file);
+
+ fail:
+ atomic_inc(&lcd_available);
+ return ret;
}
static int lcd_release(struct inode *inode, struct file *file)
@@ -1696,14 +1704,21 @@ static ssize_t keypad_read(struct file *file,
static int keypad_open(struct inode *inode, struct file *file)
{
+ int ret;
+
+ ret = -EBUSY;
if (!atomic_dec_and_test(&keypad_available))
- return -EBUSY; /* open only once at a time */
+ goto fail; /* open only once at a time */
+ ret = -EPERM;
if (file->f_mode & FMODE_WRITE) /* device is read-only */
- return -EPERM;
+ goto fail;
keypad_buflen = 0; /* flush the buffer on opening */
return 0;
+ fail:
+ atomic_inc(&keypad_available);
+ return ret;
}
static int keypad_release(struct inode *inode, struct file *file)
--
1.7.12.1
^ permalink raw reply related [flat|nested] 4+ messages in thread